| The southeastern coastal areas of China are situated in a zone known for its high frequency of typhoon occurrences.Within this region,numerous high-rise buildings and wind-sensitive structures have already been constructed.However,during strong typhoons,these structures not only face threats to their safety but also may experience excessive vibrations,impacting their fatigue life and potentially causing public panic.Thus,the features of strong typhoon wind fields and the impact of wind on high-rise buildings have been a central focus in the field of structural wind engineering for a considerable time.In-depth research in these areas holds crucial theoretical importance and practical value in advancing and refining the theory of structural wind engineering.Moreover,it provides valuable guidance for designing windresistant measures for towering and intricate wind-sensitive structures,such as super-tall buildings.Based on a combination of on-site measurements,wind tunnel experiments,and numerical simulations,this study comprehensively investigates the structural and wind field characteristics associated with typhoons impacting the southern regions of China,as well as the wind effects on high-rise buildings under strong typhoon conditions.The main contents of this article are as follows:1.Typhoon structure and wind field characteristics——In the field of structural wind engineering,there is currently a lack of research on measured data analysis in the core area of landfalling typhoons,and wind field characteristics are generally not combined with structural features for analysis.Therefore,this study selects two typhoons,"Mangkhut" and "Saola" which have had the most severe impact on the southern coastal areas of China in the past decade.Based on cross-regional and multi-source data,a comprehensive and global-scale measurement study is conducted on the structure and wind field characteristics during the landfall process of these typhoons.The main focus is to reveal the reasons why "Saola" despite having higher intensity than "Mangkhut" has a lower range of wind effects and degree of wind disaster,and its implications for the field of wind engineering.The research results indicated that eyewall replacement can significantly influence the spatiotemporal evolution and distribution characteristics of typhoon structure and wind fields.Both "Mangkhut" and "Saola" exhibited double eyewall structures over deep oceanic regions.However,in the case of "Mangkhut" the outer eyewall fragmented and stopped contracting before landfall,leading to a larger impact range but a decrease in intensity.Conversely,"Saola" experienced continuous contraction of the outer eyewall,eventually replacing the inner eyewall through the process of eyewall replacement.As a result,the typhoon’s intensity increased,but its impact range remained relatively smaller.Correspondingly,the wind fields of the two typhoons exhibited notable distinctions in terms of maximum wind speed radius,gradient wind intensity and height,and sensitivity of wind fields at different measuring points to radial distance changes.The results presented in this study demonstrate the importance of comprehensively taking into account both typhoon intensity and impact range in wind resistance research,while also considering the typical structure and evolutionary characteristics of typhoons.2.Typhoon wind effect measurement platform of super high-rise buildings——The measured data of wind effects on high-rise buildings under typhoon conditions are extremely valuable.Despite continuous efforts by researchers to establish relevant measurement platforms,existing platforms mostly focus on structural vibration measurements,while observations of multiple factors including incoming wind fields and wind pressures are less explored due to various challenges.Taking the 330-meter-tall Zhuhai Center Tower as an example,this study comprehensively utilized laser radar and health monitoring technologies to establish a measurement platform capable of synchronously monitoring the surrounding boundary layer wind fields,surface wind pressures,and structural vibration responses.Based on this platform,the wind effects characteristics of the Zhuhai Center Tower under the influence of typhoons such as "Saola" were investigated.The surface wind pressure and structural response characteristics were systematically analyzed,along with their variations in relation to incoming wind fields.Meanwhile,according to surface wind pressure and its different order moment information,an artificial intelligence inversion method was developed to estimate key parameters of the incoming wind field,such as wind speed,wind direction,and turbulence intensity.The effectiveness of this method was validated through comparative analysis.3.Field measurement study on dynamic characteristics of supertall buildings under severe wind-induced vibration——A comprehensive,long-term field measurement study was undertaken to investigate the effects of typhoon winds on supertall buildings.Successful recordings were made of significant wind-induced vibrations on supertall buildings including the Shanghai Tower(632 m),Shanghai World Financial Center(492 m),Jin Mao Tower(420m),Zhuhai Center(330 m),and Guangzhou Leatop Tower(303 m)under the influence of typhoon core regions.The recorded data revealed that the maximum unidirectional acceleration at measurement points reached 20 gal(which was relatively rare in similar studies,with few exceeding 10 gal).Based on the measured data,a key focus of the analysis was on the relationship between structural dynamic characteristics and amplitude variations.It was found that the natural frequency initially decreases and then stabilizes with increasing amplitudes,while the damping ratio tends to increase initially and then stabilize or even decrease.Moreover,it was observed that the roof drift ratio corresponding to the critical damping ratio was located in a specific range,and the mechanism behind this phenomenon was explained by incorporating the concept of equivalent damping ratio and the types of additional dampers used in the building.Additionally,the study also found that the fundamental frequency of the building slightly decreases after being subjected to typhoon forces compared to before,and potential phenomenon reasons for this were discussed.4.Effects of Reynolds number and turbulence intensity on wind effects of buildings with curved cross-sections —— By combining field measurements and wind tunnel tests,this study conducted a comprehensive investigation into the impact of Reynolds numbers,covering four orders of magnitude,and multiple turbulence intensity ranges on the wind effects of the Zhuhai Center from various perspectives,including wind pressure distribution,Strouhal number,inter-floor forces,and wind-induced responses.Furthermore,the results were compared with those of triangular and cylindrical cross-sections to elucidate the similarities and differences in the impact of arc-shaped,triangular,and cylindrical cross-sections on the wind effects of buildings.The results show that the wind load will increase with the Reynolds number or the turbulence intensity,but as both increase,their influence on the wind load will gradually decrease.5.Numerical simulation of wind pressure bimodal distribution on high-rise building—— The phenomenon of alternating positive and negative pressure on the windward side of the high-rise buildings were fond under the influence of the upstream buildings.the probability density function of pressure presents bimodal distribution obviously.Based on this phenomenon,the large eddy simulation turbulence model was used for numerical simulation research,and the simulation results were compared with wind tunnel test to verify its accuracy.The results show that the alternating vortexes on building surface originate from the shedding vortexes on both sides of the upstream building.Under the interaction with the background incoming flow,the vortex causes alternating positive and negative pressure loads on the building surface,which may cause fatigue damage to the peripheral structures of high-rise buildings.According to the above findings,a potential failure mechanism for the curtain walls and associated supporting structure under alternating load is proposed,and a mixed probabilitydensity-function(PDF)model of wind pressure signal is established.6.Urban Community Building Cluster Typhoon Wind Effect Simulation Study —— In pursuit of in-depth urban-scale wind effects on buildings,a high-resolution rapid urban modeling technique has been developed that harnesses geospatial information system(GIS)data.This study systematically investigates the inherent differences among various morphological theories when assessing the characteristics of flow field roughness.By integrating principles from source area models and morphological frameworks,an iterative algorithm has been devised to accurately compute the roughness parameters under complex terrain conditions for incoming flows.Building upon this foundation,we capitalized on the robust capabilities of gradient wind models and typhoon boundary layer models to successfully predict and simulate key parameters within the wind field.Through the synthesis of these methodologies,we have conducted a high-fidelity numerical simulation of building group wind effects at the community scale.The resulting simulations have been rigorously validated through dual scrutiny,encompassing both wind tunnel experiments and field observations,demonstrating strong consistency and reliability in their outcomes.This research sequentially delves into systematic investigations of typhoon wind effects on individual structures,multiple buildings,and building clusters,leveraging a variety of research methods.The findings contribute significantly to the advancement of structural wind engineering theories,enhancing the safety design of high-rise and super-tall buildings in coastal areas,particularly providing crucial reference value for improving their resilience during operation and maintenance stages against typhoon events. |
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